Manufacture of compound metal bodies



oct-18, 193s. F. F, GORDON 2,133,294

MANUFACTURE OF COMPOUND METALBODIES original Filed Aug. 1e,` @s

ll Vl IIll :RA u nl Il l lull' l:

Patented oci. 1s, 1938 UNITED STATES MANUFACTUBE F COMPOUND MTAL BODIES Frederick Felix Gordon, Sheffield, England Original application August 16, 1934, Serial No.

740,184. Divided and this application February 26, 1938, Serial No. 192,769.

April 12, 1934 s claims.

This application is a division of my copending application Serial No. 740,184 filed August 16h,

This invention relates to the manufacture of 5 compound metal bodies, i. e., bodies consisting of layers of metals bonded (i. e., united) together by placing a bonding material between the surfaces to be unied and effecting the union of said surfaces by means ofheat or heat and pressure.

The invention is applicable to the'bonding one to another of ordinary irons and steels and alloyed irons and steels to form compound plates, sheets, slabs, billets, ingots, tubes or other producs and is particularly useful for' the bonding of such types of metals as low and high carbon steels, high speed steels and corrosion resisting (for'example, stainless and rustless) irons and steels, but its application is not limited thereto as it may be used for many other comblna'ions of metals and alloys.

The object of the present invention isl to providef an improved method of manufacture involving the use of a bonding material which will possess suchmechanical strength that the compound body as a whole will be workable", i. e., capable of being saisfactorily subjected to heat treatment, such as annealing, hardening or tempering and mechanical treatment such as rolling,

forging, hammering or pressing or other similarV operations to'which metals and alloys may be subjected in the course of manufacture from blanks -to semi-finished and finished products.' According to this invention the bonding ma. terial-must be one which must melt or be brought to a condition suitable for forming a satisfactory bond at a temperature which does not exceed 1400u C. and is not so high as to desroy the advantageous characteristics of or otherwise injure, the metals of the bodies to be bonded but 0 which will not melt at the temperatures used for the subsequent hot working of the compound body, e. g., not below 1100 C.

As a result of my experiments I find that a bonding material consisting of the metal manganese possesses the foregoing characteristics.

According to the present invention therefore the-process for the manufacture of compound 'metal bodies with the use of an intermediatemetallic bonding material at the interfaces of the bodies and the application of heat or heat and pressure` is characterized in that manganese is used as the bonding material.

The substances usually occurring as impuri ties in the bonding material may be present. The bonding material is preferably in powdered In emi Britain form, but it may be in granular or'other solid form, e.- g., in sheet or strip form or a combination of powdered form and sheet or s'rip form. With the bonding material a flux may be used such as 'borax, sodium or potassium fluoride or 5 carbonate, resin, ammonium and'zinc chlorides or any suitable mixture of these.

The bonding material is, with the addition of about 8% of anhydrous borax or potassium fluoride Vand borax as a flux, found to be suitable 10- steels, nickel steels, ordinary alloy irons; irons,

silico manganese steels, high speed steels, high chromium steels, mild steels, ordinary carbon steels, chromium steels, ordinary alloy s' eels, and nickel chromium steels. 'g5

Where the compound metal body is, after bonding, to be worked as by rolling, forging, swaging, hammering, pressing or other mechanical operation, thesaid body should be pressed whilst hot to ensure that the compound me'al 30 body will possess such mechanical strength as to subsequently better withstand the stresses due to these aforesaid mechanical operations without risk of the bonded layers coming apart.

Where it is not convenient or desirable to 35 apply the pressure whilst the compound body is still hot' from the bonding operation, the pressure may be applied at any time afterwards by again reheatin'g the compound body, provided the compound body is reheated to approximately the 40 same temperature as was employed in the initial heating for bonding. y l

A sufficient quantity of the bonding material is used to provide a layer between the surfaces to be unitedand to substantially fill `any spaces 45 between the said surfaces.` f

If, for example, it is desired to bond a plate of corrosionresisting steel (highchromiumor.

' high chromium nickelste'el) to a mild steel slab,

the invention is carried out asv followszr-l If them surfaces to bek united `are Vno t ,lcleanthey areA preferablycleaned-by pickling, Sandblastingv or l grinding, or gotherwise. .#Between-the said su.r.l s

faces the bonding material, together with a flux, for example borax, is placed. The whole is then 55 heated until it attains a temperature of about 1325* C., at which temperature the ilrst stage of the bonding process is effected and the whole is then subjected to pressure .which completes the bonding. Whilst still sufciently hot from the bonding process the compositel slab may be reduced in cross sectional area or thickness by rolling or by some other` known process orl it may be allowed to cool and be subsequently reheated to a .suitable temperature for such reduction.

Compound metal sheets, plates, slabs or billets bonded according to my invention can be treated by subsequent processes substantially in the same manner as a single piece.

Various methods of carrying out my invention will now be described. with reference `to the accompanying drawings inwhich; e

Figs. 1 to 7 illustrate the' bonding ofslabs and sheets.

Figs. 8, 9, 10 and l1 illustrate the bonding of tubes.

Figs. 12,13 -and 14 show cross sections of compound bars.-

In Fig. 1 a layer of powdered bonding material a mixed with a flux is first placed over the surface of one side of a mild ,steel slab b and then a sheet c of corrosion resisting steel is applied, the composite body is then heated in a furnace and'pressed as hereinbefore described resulting in the `compound slab shown in Fig. 3 which can be rolled into thin sheets. Alternatively as shown inl Fig. 2 a sheet d of bonding material coated with'a flux is used instead of powdered bonding material between a mild steel slab b and a sheet c of corrosion resisting steel, the composite slab after heating and pressing resulting again in a compound slab as shown in Fig. 3.

In a further embodiment of this invention as ,whose contacting surface is preferably cleaned.

The resultant compound body is then heated as before to bond the sheets e to the adjacent slabs h and pressure is preferably applied to the hotmass, which may then be rolled or forged immediately, or after cooling and reheating. Thereafter the mass is separated at the juxtaposed and non-bonded surfaces fby removing the welded or sealed edgesg, for example, by shearing which results in two separate compound bodies.

As depicted in Fig. 5 a similar result may be obtained by bending a single sheet or slab g upon itself and applying a non-bonding or separating material between the adjacent surfaces A.1 and welding the exposed edges and then proceeding as immediately beforedescribed. l

Fig. 6 shows another method of producing a compound body by first placing together two metal bodies lc with a separating material between their juxtaposed preferably cleaned surfaces f andsealing the edges at g as before described, then placing the assembly'so defined in,

but spaced apart. from, a hollow body 1 containing at least sufficient of the powdered bonding material a to fill, when melted, the space between the bodies and. then placing the whole in amould m and .casting molten metal completely about the whole so as to heat and melt the bonding material and whereby the cast metal n becomes partof the resultant compound body, said body being adapted to be divided at the sealededges g of the non-bonded surfaces to form a plurality of compound bodies.

Still another method of producing a compound body is shown in Fig. 7 by first placing together two metal bodies o with a separating material between their juxtaposed and preferably cleaned surfaces f and sealing the edges thereof at g as l 'part of the resultant compound body, said body being adapted to be divided at the sealed edges g of the non-bonded surfaces to form a plurality o f compound bodies.

Compound tubes may be made according to my invention in a similar manner. For example as shown in Figs.` 8, 9 and 10 an outer tube r of mild steel is sealed at one end and a` quantity of the powdered bonding material a and a ux are placed therein. There is then inserted an inner tube s of corrosion resisting steel or ironalso with one end sealed the outer diameter of the inner tube being such as to leave an annular space between the two tubes. Strips of metal or wires t (Fig. 10) may be placed in the spacebetween the two tubes to ensure that the inner tube is centrally disposed. The assembly is then heated until the 4bonding material melts and completely fills the said space. For this purpose the assembly may be placed in a furnace or inan ingot mould and inA the latter case liquid steel cast around the assembly of tubes, the heat of the liquid steel causing the bonding lmaterial to melt and the cast metal forming part of the compound tube. Means such as a weight u or a spring may be arranged to cause the inner tube s to sink and thereby cause the bonding material to rise between the two tubes and bond them as shown in Fig. 9. The inner tube s is preferably somewhat longer than the outside tube r so that any excess of the bonding material does not flow into the inside of the inner tube. The compound tube is then reduced' in cross section to the requisite size in known manner or if it has been allowed to cool, is reheated subsequently and reduced in cross section.-

Tubes lined both exteriorly and interiorlycan be made in similar manner and as is shown-in `Fig. 11 by forming an assembly ofI three concentrically arranged tubes .w, a: and y with the bonding material a placed between the outer and described. For example an outer tube z ofany desired cross section may be of corrosion resisting iron or steel and the insert of similar` but smaller cross rsection may be a; solidbarv e of mild or other steel.

In the case of compound tubes and rods, it is i unnecessary to apply pressure after the bonding for the pressure exerted during the usual hot,

mechanical working of a tube or rod tends to consolidate the bond.

It is to be understood that the addition of any inert elements which do not substantially deleteriously affect' the process or the article produced thereby shall be within the scope of this invention.

What I claim and desire to secure by Letters Patent ist- 1. A process for the manufacture of a compound metal body capable of being subsequently worked, which consists in interposing throughout the interfaces of a plurality of metal bodies to be united, a metallic bonding material consisting substantially entirely of manganese and heating the assembly substantially uniformly ,throughout to a temperature which is sufficient to cause the bon-ding material to effect a satisfactory bonding y of the bodies but is below the melting points of the bodies.

2. A process for the manufacture of a compound metal body capable of being subsequently worked, which consists in interposing throughout the interfaces of a plurality of metal bodies to be united, a metallic bonding material consisting substantially entirely of manganese, heating the assembly substantially uniformly throughout to a temperture which is suilicient to cause the bonding material to effect a satisfactory bonding of the bodies but is below the'melting points of the bodies and applying pressure to the interfaces of the bodies while hot.

4. A process for the manufacture of a compound metal body according to claim 1, characterized in that the manganese is in a finely divided state.

5. A process for the manufacture of a compound metal body according to claim 1, characterized in that a flux is added to the bonding material.

6. A process for the -manufacture of a compound metal body according to claim l, characterized by the step of lsubjecting the resultant compound metal body as a whole to heat treatment and mechanical treatment.

'1. A process for the manufacture of a compound metal bodycapable of being subsequently Worked which consists in interposing throughout the outer and inner surfaces respectively of inner and outer metal bodies to be united, a rnetallic bonding material consisting substantially entirely of manganese and heating the assembly substantially uniformly throughout to a temperature which is suilicient to cause the bonding material to effect a satisfactory bonding of the bodies but .is below the melting points .of the bodies.

8. A process for the manufacture of a compound metal body capable of being subsequently worked which consists in placing a separating material between the juxtapositioned faces. of two metal bodies, applying to each of the remote faces of said bodies a further metal body and interposing throughout the interfaces of the initial bodies and the'further bodies a metallic bonding material consisting substantially entirely of manganese and heating the assembly sub'- stantially uniformly throughout to a temperature which is suilicient to cause the bonding material to effect a satisfactory bonding ofthe bodies but is below the melting points `of the bodies.

9. A process for the manufacture of a compound metal body capable of being subsequently worked, -which consists in placing a separating material between the juxtapositioned faces of two metal bodies, applying to each of the remote faces of said bodies a. further metal body and interposing throughout the interfaces of the inil tial bodies and the further bodies a metallic bonding material consisting substantially entirely of manganese, heating the assembly substanant compound metal body while hot. 

